Image forming apparatus and method for controlling image forming apparatus

Abstract

Related is an image forming apparatus by electrophotography having a function of performing adjustment of image quality when performing image formation. The image forming apparatus includes a detection portion for detecting a fixing temperature of a fixing apparatus; a storage portion for storing an application history of a development bias; a count portion for counting a reposed time from a point when an operation of image formation is ended; a determination portion for determining a change range of the development bias immediately before the end of the operation of image formation; and an execution portion for executing adjustment of image quality by setting the development bias based on a determination result from the determination portion when the reposed time or the fixing temperature exceeds a predetermined value.

1. An image forming apparatus by electrophotography having a function of performing adjustment of image quality when performing image formation, comprising:
 a detection portion for detecting a fixing temperature of a fixing portion; 
 a storage portion for storing an application history of a development bias; 
 a count portion for counting a reposed time from a point when an operation of image formation is ended; 
 a determination portion for determining a change range of the development bias immediately before the end of the operation of image formation, wherein said change range is a rise range; and 
 an execution portion for executing adjustment of image quality by setting the development bias based on a determination result from the determination portion when the reposed time or the fixing temperature exceeds a predetermined value. 
 
     
     
       2. The image forming apparatus according to  claim 1 , wherein, when the reposed time or the fixing temperature exceeds a predetermined value, the execution portion sets an effective development potential based on the determination result from the determination portion. 
     
     
       3. The image forming apparatus according to  claim 1 , wherein the execution portion sets the development bias on an average printing rate. 
     
     
       4. The image forming apparatus according to  claim 1 , wherein the change range is a range wherein a large variation occurs in an image density. 
     
     
       5. The image forming apparatus according to  claim 1 , comprising a setting portion for setting the predetermined value. 
     
     
       6. The image forming apparatus according to  claim 5 , wherein the setting portion changes the predetermined value based on deterioration in developer. 
     
     
       7. A method for controlling an image forming apparatus by electrophotography having a function of performing adjustment of image quality when performing image formation, comprising:
 a detection step of detecting a fixing temperature of a fixing portion; 
 a storage step of storing an application history of a development bias; 
 a count step of counting a reposed time from a point when an operation of image formation is ended; 
 a determination step of determining a change range of the development bias immediately before the end of the operation of image formation, wherein said change range is a rise range; and 
 an execution step of executing adjustment of image quality by setting the development bias based on a determination result from the determination portion when the reposed time or the fixing temperature exceeds a predetermined value. 
 
     
     
       8. The method for controlling the image forming apparatus according to  claim 7 , wherein, when the reposed time or the fixing temperature exceeds a predetermined value, at the execution step, an effective development potential is set based on the determination result at the determination step. 
     
     
       9. The method for controlling the image forming apparatus according to  claim 7 , wherein the development bias is set based on an average printing rate at the execution step. 
     
     
       10. The method for controlling the image forming apparatus according to  claim 7 , wherein the change range is a rise range wherein a large variation occurs in an image density. 
     
     
       11. The method for controlling the image forming apparatus according to  claim 7 , comprising a setting step of setting the predetermined value. 
     
     
       12. The method for controlling the image forming apparatus according to  claim 7 , wherein the predetermined value is changed based on deterioration in developer at the setting step.